What direction is this exposure? Full sun all afternoon? Is the bed sprinklered?

Oops. Left that out. The house is south facing. The only irrigation is rain and me standing there with a hose.

Some years I fill this area with annuals, but that adds up every year. Vinca does well, even though there is quite a bit of afternoon shade on the left half.

The bed comes out eight feet.

I love variegated liriope.....i planted eight of them on the other side of the house this morning. :)

I don't think a single plant across the entire front is going to be your best option. I would flank the steps with a low/medium dome plant that could hide step edges -- as cheekwalls would do. You could plant something similar that wraps the porch corner, as "bookends," or something entirely different. At any rate, at the corner, I wouldn't exceed beyond half the height of the railing. Then you could fill in between each end with a perennial that is happy with the existing light conditions. It could cover the foundation area, but I wouldn't let it get much higher than the porch floor. A plant the covered the foundation but has lots of blooms sticking up higher would be great for having a seeing a lot of color from the porch or house interior.

Yardvaark, I think you're right. Any suggestions for a perennial that meets that description? Thanks!

A couple of perennial recommendations:

Purple Palace Heuchera: a good sized Heuchera, it's blooms can reach nearly 2', plus the purple foliage will give interest all spring and summer.

All Gold Japanese Forest Grass: this plant will need afternoon shade for sure, but it keeps it's bright foliage so beautifully; it's a favorite to brighten up a shady bed.

Sum and Substance Hosta: another option for chartreuse/lime foliage, these can be a sensitive to burning in the sun.

For blooms:

Helleborus or Christmas Rose, white or pink cultivar: these are a little smaller, but will be among the first blooming perennials to peek out in spring.

Astilbe: the tufted shape of the bloom pairs really well with the mounding shape of hydrangeas.

If you would like an evergreen, but are worried about size, a Slowmound Mugo Pine, Dwarf Blue Shag Eastern White Pine, or Sea Urchin Pine all live up to their dwarf plant title. None of them will get taller than 3', excluding the Blue Shag which can on occasion reach close to 4'. These will all need to have sun though, so won't be suitable for the shadier side of the porch.

I hope these recommendations help a bit!